1. Field of the Invention
The invention relates generally to management of Serial Advanced Technology Attachment (SATA) system and more specifically relates to methods and structure for capturing error information regarding operation of a SATA device for evaluation by analytical devices.
2. Related Patents
This patent is related to commonly owned U.S. patent application Ser. No. 11/644,549 entitled Serial Advanced Technology Attachment (SATA) and Serial Advanced Small Computer System Interface (SCSI) (SAS) Bridging” which is hereby incorporated by reference. This patent is also related to commonly owned U.S. patent application Ser. Nos. 08-0382 and 07-2480 filed herewith which are also hereby incorporated by reference.
3. Discussion of Related Art
Storage systems may incorporate any number of storage devices (e.g., disk drives, CDROMs, etc.) ranging from a single storage device in a personal computer or workstation to hundreds if not thousands of storage devices in large scale storage applications. SATA storage devices are popular as low cost devices that provide adequate performance for many storage applications. SATA protocols utilize a high speed serial link to transmit frames between an initiator device (such as a host system or storage controller) to a target device (such as a disk drive or other storage devices). The SATA frame exchanges include information relating to register values that were previously exchanged over a parallel bus structure (PATA).
SATA exchanges are often embedded within a Serial Attached SCSI (SAS) networks wherein one or more SAS initiators communicate via a network of zero or more intermediate SAS expanders to one or more target devices. Where the target devices are SATA devices, a SAS initiator may connect to the SATA target device such that the SATA protocol is embedded (“tunneled”) within the SAS standards using the SATA Tunneling Protocol (STP).
Regardless of the connectivity to a SATA target device (i.e., direct attachment to a SATA initiator or attachment to a SATA initiator through a SAS network using the STP protocol) it is a challenge to debug errors that arise in processing of the SATA exchanges. The SATA protocols between an initiator and a SATA target device do not provide a mechanism to capture, display, or otherwise present to an engineer any useful error information beyond the SATA frames per se. Design or field engineers need such additional error information to evaluate or debug a detected problem in communications with a SATA target device. Though the initiator device may have useful information to aid in determining the underlying problem there is no standardized SATA protocol exchange to permit that information to be presented to the engineer. Thus it is an ongoing challenge to obtain useful information to identify and correct a problem in a SATA device coupled to an initiator device.